Thanks for the helpful reply, equator. I've also been digging around for info. Some say to just buy a sound card and plug directly, while others go the usb route. In summation, are these set ups correct:

acoustic guitar + x -> preamp -> usb interface (no need for soundcard) -> pc (audacity/reaper)

acoustic guitar + x -> preamp -> plug adapter + mac (garageband)

x being a pickup, transducer or clip on condenser mic-- I've been reading the mic is the best option. did i understand that correctly? or choosing any of the 3 doesn't make a difference? can the condenser mic be also used for vocals?

is this the most cost effective way to amaturely record with good quality?

also, since both setups are w/o amps, w/o soundcard upgrade and are computer based, can i practice on both set ups with headphones? I know that might sound like a silly question, but I'm not good with technicals and I think input/outputs must have wattage compatibilities or something.... or i can just be overthinking this, lol...

lastly, if you record, do you need tons of hard disk space? I know video editing does, does audio recording consume considerable space too (tho not as much as video, of course)?

thanks again!